Question

可以通过 subgraph 命令建立子图，其语法为：

subgraph title
  graph definition
end

如：

~~~mermaid
graph TB
subgraph one
	a1-->a2
end
subgraph two
	b1-->b2
end
subgraph three
	c1-->c2
end
c1-->a2
~~~

的图形为：

~~~mermaid
graph TB
subgraph one
a1-->a2
end
subgraph two
b1-->b2
end
subgraph three
c1-->c2
end
c1-->a2
~~~